Due to unintended idiocy on my part, I failed to notice that the instructions for installing Battlegroup 42 say that any existing BG42 folder should be deleted before installing a new version. In my defense, the BG42 installer should check for existing folders and offer to remove them or at least warn the user. Anyway, the result of my error was that some BG42 maps on the server were using a mixture of new and old data and those maps were causing client and server crashes. The old files have been removed and the maps previously removed from the rotation have been reinstated. Please let me know if there are any more crashing problems with BG42 maps.